SAN ANTONIO — The addition of enzalutamide to exemestane significantly prolonged PFS and appeared well tolerated among patients with hormone receptor-positive metastatic breast cancer who had not received prior endocrine therapy and who expressed an androgen receptor gene signature, according to results of a placebo-controlled randomized phase 2 trial presented at the San Antonio Breast Cancer Symposium.

Androgen receptor signaling — expressed in more than 75% of hormone receptor-positive tumors — has been associated with resistance to endocrine therapy.

PFS in the intention-to-treat population, as well as in a gene-signature based biomarker cohort indicating androgen receptor signaling predictive of response to enzalutamide, served as the study’s primary endpoint. Secondary endpoints included clinical benefit at 24 weeks, best overall response and safety.

“The role of the androgen receptor in hormone receptor-positive breast cancer and the predictive value of the identified biomarker are still unclear and will require further studies,” Yardley said. – by Alexandra Todak

SAN ANTONIO — The addition of enzalutamide to exemestane significantly prolonged PFS and appeared well tolerated among patients with hormone receptor-positive metastatic breast cancer who had not received prior endocrine therapy and who expressed an androgen receptor gene signature, according to results of a placebo-controlled randomized phase 2 trial presented at the San Antonio Breast Cancer Symposium.

Androgen receptor signaling — expressed in more than 75% of hormone receptor-positive tumors — has been associated with resistance to endocrine therapy.

PFS in the intention-to-treat population, as well as in a gene-signature based biomarker cohort indicating androgen receptor signaling predictive of response to enzalutamide, served as the study’s primary endpoint. Secondary endpoints included clinical benefit at 24 weeks, best overall response and safety.

“The role of the androgen receptor in hormone receptor-positive breast cancer and the predictive value of the identified biomarker are still unclear and will require further studies,” Yardley said. – by Alexandra Todak